McArthur scored a goal that had been coming for some time for Palace, drawing the sides level in the 68th minute with a goal to cancel out Xherdan Shaqiri's opener.
The visitors broke through Wilfired Zaha, then Ruben Loftus-Cheek, who made up for his earlier error for the first goal, feeding McArthur down the right.
The Scot hit a composed finish back across goal, beating Wayne Hennessey to make it 1-1. The goal dealt a big blow to Stoke's survival chances, as they were desperate for a win to keep their dreams afloat.